[R] extracting estimated covariance parameters from lme fit

Dear all Apologies in advance as this seems like a trivial question. Nonetheless, a question I haven't been able to resolve myself !. Within a single repetition of a simulation (to be repeated many times) I am fitting the following linear mixed model using lme... Y_{gtr} = \mu + U_{g} + W_{gt}

Re: [R] extracting estimated covariance parameters from lme fit

The VarCorr function will extract the components of the random effects covariance matrix, but note the quirk that it returns values as characters: library(nlme) f1 - lme(distance ~ age, data = Orthodont, random = ~1 + age|Subject) (vc - VarCorr(f1)) # Subject = pdLogChol(1 + age) #